<!DOCTYPE html>
<head>
<title>Test AudioContext.setSinkId() state change</title>
</head>
<script src=/resources/testharness.js></script>
<script src=/resources/testharnessreport.js></script>
<script>
"use strict";

let outputDeviceList = null;
let firstDeviceId = null;

// Setup: Get permission via getUserMedia() and a list of audio output devices.
promise_setup(async t => {
  await navigator.mediaDevices.getUserMedia({ audio: true });
  const deviceList = await navigator.mediaDevices.enumerateDevices();
  outputDeviceList =
      deviceList.filter(({kind}) => kind === 'audiooutput');
  assert_greater_than(outputDeviceList.length, 1,
                      'the system must have more than 1 device.');
  firstDeviceId = outputDeviceList[1].deviceId;
}, 'Get permission via getUserMedia() and a list of audio output devices.');

// Test the sink change when from a suspended context.
promise_test(async t => {
  let events = [];
  const audioContext = new AudioContext();
  await audioContext.suspend();

  // Step 6. Set wasRunning to false if the [[rendering thread state]] on the
  // AudioContext is "suspended".
  assert_equals(audioContext.state, 'suspended');

  // Step 11.5. Fire an event named sinkchange at the associated AudioContext.
  audioContext.onsinkchange = t.step_func(() => {
    events.push('sinkchange');
    assert_equals(audioContext.sinkId, firstDeviceId);
  });

  await audioContext.setSinkId(firstDeviceId);
  assert_equals(events[0], 'sinkchange');
  t.done();
}, 'Calling setSinkId() on a suspended AudioContext should fire only sink ' +
   'change events.');

// Test the sink change on a running AudioContext.
promise_test(async t => {
  let events = [];
  let silentSinkOption = {type: 'none'};
  const audioContext = new AudioContext();

  // Make sure the context is "running". This also will fire a state change
  // event upon resolution.
  await audioContext.resume();

  return new Promise(async resolve => {

    function eventCheckpoint() {
      // We're expecting 4 events from AudioContext.
      if (events.length === 4) {
        // The initial context state was "running".
        assert_equals(events[0], 'statechange:running');
        assert_equals(events[1], 'statechange:suspended');
        assert_equals(events[2], 'sinkchange');
        assert_equals(events[3], 'statechange:running');
        resolve();
      }
    }

    // This is to catch a sink change event:
    // - Step 11.5. Fire an event named sinkchange at the associated
    //   AudioContext.
    audioContext.onsinkchange = t.step_func(() => {
      assert_equals(audioContext.sinkId.type, silentSinkOption.type);
      events.push('sinkchange');
      eventCheckpoint();
    });

    // The following event handler will catch 3 state change events:
    // - The initial 'running' state change.
    // - Step 9.2.1. Set the state attribute of the AudioContext to "suspended".
    //   Fire an event named statechange at the associated AudioContext.
    // - Step 12.2. Set the state attribute of the AudioContext to "running".
    //   Fire an event named statechange at the associated AudioContext.
    audioContext.onstatechange = async () => {
      events.push(`statechange:${audioContext.state}`);
      eventCheckpoint();
    };

    // To trigger a series of state changes, we need a device change. The
    // context started with the default device, and this call changes it to a
    // silent sink.
    audioContext.setSinkId(silentSinkOption);
  });
}, 'Calling setSinkId() on a running AudioContext should fire both state ' +
   'and sink change events.');
</script>
</html>
